Method of making paper boxes



Sept. 29, 1 936.

c. 1.. CLAFF METHOD OF MAKING PAPER BOXES Filed Nov. 27, 1955 2Sheets-Sheet l Sept. 29, 1936. c CLAFF 2,056,094

METHOD OF MAKING PAPER BOXES Filed Nov. 2'7, 1935 2 Sheets-Sheet 2Fntented Sept. 29, E33

titre sites getter an airmen I This invention relates to paper boxes andmore especially to a method of making boxes from box board material.

Heretoiore in the construction of boxes it has been the practice to cuta blank, fold the sides and side wings, thereafter applying the end foldto the outer surfaces of the wings and axing it thereto with a lightpressure, and subsequently bending the end fold into the box so as tostraddle the end wings, at which time the fold is subjected to a heavypressure to flatten it and complete the formation of the box.

While the operation described has been ef== fective the resultant boxhas been objectionable for certain reasons. For example, if it has beendesired to reduce the thickness of the exposed side edges of the endfold a separate operation has been required. Furthermore the final heavycompression to which the end of the box has been subjected following theinitial light pressure, has,

resulted in an extrusion or shift of the material of the end told at itsbend which has caused said fold to protrude an objectionable distancewhere straddling the inturned side wings, thus produc ing an unsightly,uneven appearance on the box lid or box produced by the method.

An object of the present invention is to avoid the disadvantages statedby improving upon the method of producing the boxes whereby, through theapplication of a heavy initial pressure the end fold, while partlyfolded, is aflixed to the inturned wings, compressed at its side edgesto reduce the thickness of said edges and allowed to extrude or elongatetoward its free end prior to the final bending of the fold down over thewings so that this added area of the fold can be compensated for bybending the fold after the extrusion or extension has taken placeinstead of prior thereto, thus to reduce the objectionable bulging bendin the fold and render it less conspicuous.

Another object is to subject the completely folded box to a lightpressure as a final step in the method, this pressure being sumcientmerely to bring the several thicknesses of the box end together toinsure proper adhesion.

With the foregoing and other objects in view which will appear as thedescription proceeds, the invention consists of certain novel details ofconstruction and combinations of parts and in certain steps of themethod hereinafter more fully described and pointed out in the claims,it being understood that changes may be made in the construction andarrangement of parts and in the disclosed method without departing fromthe spirit of the'invention as claimed.

In the accompanying drawings the preferred form of the invention hasbeen shown.

In said drawings:

Figure l is a plan view of one end of a shaped blank prior to thefolding operation.

Figure 2 is a similar view showing the sides and side wings bent toproper positions.

Figure 3 is a section on line 3t, Figure 2.

Figure 4 is a plan view showing the end fold raised against the wings.

Figure 5 is a horizontal section through the end of the box with aformer and a pressing and shaping die applied thereto while the end foldis in the position shown in Figure 2.

Figure 6 is a section on line 5-6, Figure 5.

Figure 7 is a section on line 71-11, Figure 6.

Figure 8 is a plan view of the folded end of the completed box.

Figure 9 is an enlarged section on line 99, Figure 8.

Figure 10 is a side elevation of said end showing', by broken lines, theapproximate position or the bend in the end fold if the present methodis not followed.

Figure 11 is an elevation of one side portion of the end orfront of thecompleted box.

The present method includes, first, the formation of a blank 5 havingsides 2 and side Wings 3. The blank can also be made with an integralend fold 6 although, if preferred, this end can be a separate piece suchas shown, for example,

' in the patent to Clair No. 1,579,646 dated April Following the shapingof the box members, the sides 2 are bent perpendicularly to the bottomof the blank and the wings 3 extended toward each other as shown inFigure 2.

The end fold t is next applied to the wings 3 in an unfolded conditionas in Figure 4 and at the same time a. former A within the box and ashaping and compressing die B are moved toward each other to subject thewings 3 and the engaged portions of the fold to very heavy pressure. Thedie B has rounded or beveled shoulders C adapted to press against theside edges of the end fold so that during this initial and heavycompression, said edges will be so compressed and shaped or embossed asto cause the finishing or covering paper 5 on the fold to partly orentirely cover the raw side edges of the die-engaged portion of thefold. This has been illustrated in Figures 5 and '7.

Usually at this stage of the known methods of making boxes, the end issubjected to a. pressure only sufficient to hold the end foldmomentarily against the wings to insure adhesion. Thereafter the freeportion of the end fold has been turned down into the box and the entireend then subjected to a very heavy pressure. This has resulted inforcing the bent or fold portion of the end fold upwardly away from itsoriginal position, as shown for example by broken lines at :z: in Figure10. Thus an objectionable bulge has been produced showing raw edges andforming an open-ended'loop.

In the present invention, however, the initial heavy compression of thepartly folded end between the former and the die not only shapes theside edges of the engaged portion of the end fold and afiixes saidportion to the wings 3, but it also causes any upward displacement, suchas extrusion or stretching, to occur before the final bend occurs, asshown by the arrow in Figure 6. Therefore when the final step occurs ofturning or bending the end fold over the edges of wings 3 and down intothe box, the bend or turn 6 of the fold will hug closely to the edges ofthe wings, as shown by full lines in Figures 9 and 10 so that the extentof the protrusion of the bend above said edges will be reduced to theminimum, which is the thickness of the material of the fold.

It is to be understood, of course, that the term box" herein used is toapply to either the body or the cover of a box, both of which can bemade by the same method.

What is claimed is: I

1. A method of producing boxes which includes the steps of inturning theside wings of a blank, applying the outer portion of an end fold to theouter faces thereof under a pressure suflicient to emboss the opposedside edges of the engaged portion of the-end fold and tightly compressthe lapping portions of the box, subsequently bending the end foldsnugly over the edges of the wings and into the box, and finallysubjecting the bent end fold to a light pressure sufficient to cause itto bear against the wings without displacing the bend of the fold.

2. A method of producing boxes which includes the steps of inturning theside wings of a blank, applying the outer portion of an end fold to theouter faces thereof, subjecting the lapping portions of the wings andfold to compression sufficiently heavy to emboss the opposed side edgesof the fold, and allow extrusion or stretching of the material of thefold into its uncompressed portion, thereafter bending the uncompressedportion of the end fold snugly over the edges of the wings and into thebox, and finally subjecting the inturned portion of the end fold to apressure suflicient to bring it against the inner faces of the wingswithout displacing the bend of the fold relative to the edges of thewings.

CLARENCE LLOYD CLAFF.

